The application of thin-film metamaterials as thermal emitters for thermophotovoltaics (TPV) transforming heat to electricity is limited due to the low-melting metals. The synthesis by magnetron sputtering of selective absorber/emitter metamaterials with high-melting refractory metals, nitrides as well as carbides for highest temperatures (> 1000°C) is the scientific challenge in this SFB part project. The investigations are focused on thermal stability of layered metamaterials using the strong expertise of our SFB especially HR-TEM of Z3 (see above: stack of 7 nm Au/42 nm Si). The layer design of metamaterials such as length scales, materials, interlayers and microstructure will be adjusted and optimized for highest achievable work-ing temperatures and required optical properties. Promising combinations of metamaterials (see below: with a diffusion barrier) are selected by simulation and characterization of the optical performance in collaboration with C1. Film growth, diffusion processes and recrystallization of layered metamaterials is analyzed in order to understand structural and chemical changes at high temperatures using synchroton radiation and photo-electrons (Z2 and A7). Advanced stacks of different metamaterials can open the second hierarchical level to hyper-crystals for new functionalities.
|Dr. rer. nat. Michael Störmer, |
thin films hyper crystals
magnetron sputtering IR emitter/absorber
1. P. Dyachenko et al.: Controlling thermal emission with refractory epsilon-near-zero metamaterials via topological transitions. Nature Commun. 7, 11809, 2016 - with C1
3. S. Lang et al.: Gold-silicon metamaterial with hyperbolic transition in near infrared. Appl. Phys. Lett. 103, 021905, 2013 - with C1
... and more on the list of publications.